Driving on Sunshine
What’s the real deal with electric vehicles?
I hope you’re reading this because a friend sent you the link. Whether you believe electric cars are a great idea or a huge hoax, here are a few true facts to help you understand why we’ll all be driving on sunshine soon.
Fact #1: Electric Vehicles Burn Through a Lot Less Stuff
Fuel-burning cars are a bit lighter than battery electric vehicles (BEVs). From this fact some people wrongly conclude that driving fuel-burning vehicles uses fewer resources than driving BEVs. In fact, even if you burn fuel to generate the electricity used to recharge batteries, over the course of their useful lives, BEVs burn through a lot less stuff than internal combustion engine (ICE) vehicles do.
Back in the day, tiny print on electronic toy packaging often said, “Batteries not included.” Gas powered cars are like that: gas is not included. To drive 26,000 miles in a car that gets 26 miles to the gallon, you’ll need to buy one thousand gallons of gasoline. Since the average American drives about 13,000 miles per year and each gallon weighs about six pounds, that’s three thousand pounds of more stuff to buy every year to make the car go.
According to Progressive Insurance, a conventional gas-powered car should last 200,000 miles. The US Department of Energy reports that the average fuel economy of cars sold in the United States reached a record high of 25.7 miles per gallon in 2020. At that fuel economy, a new car will burn through more than 46,000 pounds (23 tons) of gasoline during its useful life. Since the average car weighs between 2,500 and 4,200 pounds, fuel outweighs everything else by about 11 to 18 times.
But wait, gasoline doesn’t just stream down freely from the sky into the pumps at every gas station on Earth. Each gallon consumes energy to produce and transport. To produce fossil fuel it takes more fossil fuel (the petroleum refining sector is the largest consumer of fuel in US manufacturing), plus a little bit of electricity, which is sold in units called kilowatt hours (abbreviated “kWh”). Depending on who you believe, to produce a gallon of gasoline fuel requires about 8% more fuel plus between 0.2 and 2.1 kWh of electricity.
So to the total fuel required for a gasoline-burning car, add 3,680 pounds for more fuel used in the refining process plus between 1,500 and 16,000 kWh of electricity, to bring the gas car total to 53,680 pounds of fuel plus between 1,500 and 16,000 kWh of electricity.
How does that compare to an electric vehicle? Batteries are included with electric cars. That makes the average electric car about one thousand pounds heavier than a gas car. The curb weight of a Bolt EV, for example, is between 3,589 and 3,624 pounds. A Tesla Model 3 weighs between 1,617 and 1,900 kilograms (since they are sold internationally, Teslas report their weight in metric units); but when you multiply that by 2.2 to get pounds it works out to about the same weight as a Bolt: 3,557 to 4,180 pounds.
But how to account for recharging the battery? Electric vehicles don’t need fuel; they need power. While the efficiency of gas vehicles is measured in miles per gallon, the efficiency of electric vehicles is measured in kWh per 100 miles. A Tesla Model 3, for example, has a “fuel economy” of 25 kWh/100 miles.
To drive 200,000 miles in your Tesla will require 50,000 kWh of electricity to charge the battery again and again. Since the battery in a Model 3 Tesla has a capacity between 50 kWh and 82 kWh, that could mean up to one thousand discharge-charge cycles. Lithium ion batteries last for at least 2,000 cycles and over 3,000 if well cared for, so at 200,000 miles most electric vehicles are middle aged.
Confusing fuel and energy is where most EV bashers go off the rails. They say, “Well didn’t you know that we have to burn tons of coal to generate the electricity to power your car?”
Actually, we don’t. To generate one kWh, you could burn 1.12 pounds of coal, 7.36 cubic feet of natural gas, 0.08 gallons of petroleum liquids, or 0.82 pounds of petroleum coke. Or you could let water flow through a hydropower turbine, wind blow through a wind turbine, or sunlight shine on a photovoltaic panel. The US Energy Information Administration provides a slick data browser that shows which methods are being used to make electricity for you. Here’s the mix for Maine for January 2023 (not exactly our best month for solar):
If you live in Maine, intend to buy all your electricity from the grid, and want to drive your electric car 200,000 miles, how much fuel will need to be burned to generate all the electricity necessary?
The answer depends on how soon the huge amounts of wind (over 42 GW), battery (over 20 GW) and solar (over 11 GW) in the queue of upcoming projects awaiting permission to start generating power for New England (Maine is connected to the New England Power Pool) get built. It’s very possible that we’ll be generating electricity soon without burning any fuel.
But let’s assume that our power supply will stay the way it was in January 2023, with a lot of biomass and natural gas in the mix. Using electricity made in Maine, you’d burn through about 0.29 pounds of various types of fuel per kWh, for a total of 14,487 pounds of fuel to produce 50,000 kWh of electricity.
So to sum up it all up:
- Gas powered car:
~53,680 pounds of curb weight plus fuel burned
+ 1,500 to 16,000 kWh (434 to 4,636 pounds of fuel) to produce fuel
= > 54,000 pounds total - Electric car:
~4,000 pounds of curb weight
+ 50,000 kWh (requiring 14,487 pounds of fuel) to charge battery
= < 20,000 pounds total
Fact #2: Life Cycle Analysis Misses a Moving Target
Before the current era of practical electric vehicles, made possible by the mass manufacturing of lithium ion batteries, it was generally sensible to encourage anyone interested in saving the planet to buy a used gas powered car or truck with good fuel economy. In that previous era, the total impacts of making a new vehicle were greater than keeping an older vehicle on the road.
Adding up all the costs of research and development, mining, manufacturing, selling, operating and disposing of a product is called life cycle analysis (LCA). Many people have tried comparing the total life cycle costs of electric versus gas vehicles. The problem with LCA for electric vehicles is that most of the impact of an electric vehicle depends on how the batteries are recharged not how the batteries are made. Emissions from electricity and fuel to operate the vehicle far outweigh the emissions to manufacture the vehicle.
The chart above compares greenhouse gas emissions from battery electric vehicles, using two different assumptions about how the batteries are made, against the greenhouse gas emissions from an internal combustion vehicle. Those error bars in the orange electricity portion of the LCA analysis show the issue. How the batteries are made makes little difference; the important consideration is how the electricity is generated. Make one set of assumptions about how electricity will be generated, and electric vehicles have almost the same impact as gas vehicles. Make another, and they are way better. In fact, how we are generating electricity is changing rapidly, in the direction of much more wind and solar and much less coal. So those orange sections will probably be much smaller in the future.
The amount of solar electricity has just caught up to the amount of hydroelectricity we produce in the United States. Wind surpassed hydro back in 2020. Coal has now fallen way below natural gas, and is neck and neck with nuclear. Zooming in on the growth of renewable electricity generation in the last five years, you can see how fast solar is growing.
In winter months we’re producing more than 10,000,000,000 kWh of solar electricity (enough to drive 40 billion miles per month) and in summer we’re producing enough to drive 80 billion miles per month. That’s already enough solar to cover about 20% of our trips, since Americans drive about 3,200 billion miles per year, or 266 billion miles per month on average. There’s nothing stopping solar energy from quickly growing in capacity to power 100% of the miles Americans drive.
If you keep a gas powered car on the road, you’ll be buying gasoline to operate it. There’s no doubt about that. But if you buy an electric vehicle, there’s a good chance it can run on sunshine its whole life. All it takes is you or your neighbors to put some panels in a sunny place to collect the free energy streaming down from the sky, store the solar electricity in a battery, and put in a plug where you park your car.
If you’re arguing with someone about the relative environmental merits of electric versus gas vehicles, the next question will be, “What is the life cycle cost of solar power?” I’ll tackle that in a future article.
Fact #3: Each Pound of Fuel Produces More Than Three Pounds of Pollution
If you choose to use a gas car to get around, you’ll be tying up between 2,500 and 4,200 pounds of metal, glass and plastic until your car gets crushed and most of that material gets recycled. Meanwhile, the approximately 50,000 pounds of fuel you burn will combine with oxygen to emit 158,000 pounds of carbon dioxide pollution that will hang out in our atmosphere for centuries. This tips the sustainability scale even further in favor of electric vehicles.
If you’re at all alarmed about climate change, this fact alone could persuade you to ditch your gasmobile and start driving electric.
Fact #4: Batteries Can Be Recycled and Reused
Virtually every car sold has a battery in it. Since the 1950s, 12-volt lead-acid batteries have been the standard. Lead being highly toxic, people have been pretty good about recycling those batteries.
In the 2020s lithium-iron-phosphate batteries (not the ones containing cobalt) are becoming the new standard chemistry, with sodium-ion coming on fast. Anticipating the need to recycle batteries at scale, companies like Redwood Materials are ramping up to collect, refurbish, recycle, refine and remanufacture battery materials. Whether pyrometallurgy (mechanically shredding batteries and then burning them) or hydrometallurgy (dissolving batteries in pools of acid) or a mix of the two techniques will be more effective is still an open question.
While some companies are exploring recycling methods, many others are finding ways to extend the useful life of battery packs after taking them out of vehicles. RePurpose Energy, for example, is focused on “second-life” stationary applications to reuse electric vehicle batteries before they are recycled.
Critics will point out that even though we can recycle lithium ion batteries, we are not recycling many of them yet. Whether we actually need to recycle them or not will depend on the relative cost of mining virgin lithium versus recycling. There’s no shortage of lithium in the world.
Fact #5: We Can Handle the Power
During a heat wave in 2022, the California Independent System Operator, which manages the state’s power grid, asked people, including electric vehicle owners, to limit their power use between 4 pm and 9 pm on the Wednesday and Thursday before Labor Day. During a July heat wave in Texas, Tesla made a similar request asking its customers to refrain from charging their cars during peak times.
Is our power grid is on the edge of catastrophe? Will adding the additional load of charging electric vehicles push it over the edge? Nope and nope.
There are two primary reasons our power grid can easily handle electric vehicles. First, all things considered, there just aren’t that many electric vehicles. In 2022, fewer than one million electric vehicles were sold in the United States. It will take time for car manufacturers to scale up production, and as that happens we can be adding solar panels to our homes and carports.
Second, unlike air conditioners, which all kick on at the same time when a heat wave comes through, vehicles can be scheduled to charge whenever power is available. You can plug in when you get home, but tell your car not to start charging until the middle of the night when electricity rates are low and your local power grid has excess capacity.
If your power grid did start to infringe on your plans to charge your car, the solution is obvious — if you own your own home. Install solar panels. Use them to charge a stationary battery. Then use that stationary battery to charge your vehicle whenever you want.
You can figure out how many solar panels you need to drive on sunshine if you have a few data points:
- How many miles you drive per year.
- The efficiency rating of your electric vehicle.
- The power rating of your solar panel.
- Solar production data available from PV Watts.
For example, driving 20,000 miles per year in a Tesla Model 3 requires 5,000 kilowatt hours of electricity per year, which PV Watts shows can be produced by ten 400 watt panels in a sunny location (a roof, awning, carport, pavilion or ground mount) in southern Maine.
For extra peace of mind in case you’re worried about getting stuck at home in a blizzard during a power outage, you might even buy a generator and a few gallons of fuel. Burn the fuel to generate power and use the power to charge your car battery. In a portable generator, one gallon of gasoline can produce over 7 kWh of electricity, which means a Tesla Model 3 gets about 30 miles per gallon of gasoline burned in a portable generator: that’s more fuel efficient than burning gasoline directly in the average new car sold in 2023. Not a great plan compared to solar, but handy for an emergency or natural disaster.
If you don’t own your home and your landlord won’t install solar panels, then get to know your local politicians. With the right public policies in place, you could start getting parking lots covered with solar panels, storing energy in stationary batteries, so you can plug in whenever you park.
Two more salient facts before I let you go:
- Solar power for charging electric vehicles won’t work everywhere. That’s okay. If you can’t get power from your own solar panels, you can buy power from a nearby solar farm. The most important thing is bringing power to parking spaces so you can plug in where you park.
- Electric cars are still too expensive. Price is the most important factor in consumers’ vehicle purchasing decisions. It will take until 2024 or 2025 before economies of scale bring down the price of electric vehicles below gas-powered equivalents.
As solar power and electric vehicles become more available and affordable, we’ll all be driving on sunshine.